1. Technical Field
The present invention relates a highly soluble gelling vegetable protein product, and to a process for obtaining such product.
2. Background of the Invention
Meat injection is widely used in the food industry in order to increase the juiciness and tenderness of the meat, as well as to increase the yield thereof. Typical injection brines consist of nitrite salt, dextrose, phosphate, ascorbic acid, and a protein source such as soy protein. In order to obtain the desired product quality, the brine must disperse rapidly within the muscle fibers and support or strengthen the meat protein gel formed under the processing conditions. In addition, the injected brine should also be retained within the muscle fibers.
Typical protein sources are viscous and only partly soluble. These sources often have a somewhat impaired dispersion ability due to insoluble particles and high brine viscosity. Also, the amount of protein product which can be included in a brine formulation is limited by the degree of viscosity imparted. Further, gelling is typically not complete at the relatively low temperatures typically used for meat pasteurization, and the strength of the gel is diminished in salt.
There is a need for a brine containing an improved protein source, which allows for good dispersibility, gel formation at low temperatures, good binding properties for the brine and the ability to be included at high levels in the brine formulation. Some attempts have been made to arrive at such a product based on soy protein.
Vegetable protein based meat analog products or gelling food products, for example cheese and yogurt, offer many health benefits to consumers. Consumer acceptance of these products is directly related to organoleptic qualities such as texture, flavor, mouthfeel and appearance. Protein sources for gel-based food products such as meat analogs, like those useful in pickling brines, must have good gel forming properties at relatively low cooking temperatures and good water and fat binding properties. Typically, vegetable proteins and combinations of vegetable proteins such as vital wheat gluten and soy protein isolate will form viscous mixes, prior to cooking, which are difficult to handle in pumping and forming equipment. Also, the cooked products from these protein sources are typically significantly different in chewiness or xe2x80x9cbitexe2x80x9d from the natural texture of processed meat products or gelled food products. There is a need for vegetable protein sources which will support improved handling properties of mixtures before cooking and improved texture of cooked products.
U.S. Pat. No. 5,663,058 discloses a process for producing a soybean protein material comprising the steps of hydrolyzing soybean protein, emulsifying an oil-and-fat ingredient with the soybean protein and drying the mixture. The product is said to have taste, color and water-dispersibility suitable for use as a pickling solution at high concentrations and in viscous liquid foods such as soup.
The present invention relates to a process to obtain a highly soluble, salt tolerant, low viscosity, gelling vegetable protein product. When introduced into a suitable meat injection brine, the protein product is capable of forming a firm sliceable meat piece with high water retention, having no visible signs of the injected brine. When included in suitable vegetable protein-based formulations which simulate cooked processed meat products or gelled food products, the protein product is capable of forming firm, sliceable pieces or the typical gel character of the food product. The invention is illustrated by the preparation of a soy protein powder.
The present invention provides a protein source for meat injection, which has not been hydrolyzed, and is characterized by a very high dispersibility and solubility and low viscosity, which enables the product to readily distribute itself in between the meat fibers in the injected meat piece.
More specifically, the present invention discloses a native vegetable protein product, which is highly soluble in water, low in viscosity, and forms a gel at mild heat treatment. The product forms a gel at a temperature of between 60 and 105xc2x0 C., preferably at a temperature of between 70 and 90xc2x0 C.
The product is further characterized in that it has a protein content between 60% and 82% moisture free basis, and an NSI (nitrogen solubility index) of between 50 and 100. The product is further characterized by having a viscosity of 5-50 centipoises, preferably 5-25 centipoises, measured on a 10% dispersion by weight, in water. In addition, the product may contain a high amount of soluble sugars. As a preferred protein, soy protein is used.
A process is disclosed for obtaining the native protein product, including the steps of:
dispersing purified protein with high PDI (protein dispersability index) in water around neutral pH;
extracting the dispersion;
centrifuging the dispersion to remove the insoluble fraction;
optionally lowering the pH of the supernatant fraction to 5.0;
neutralizing;
optionally removing low molecular weight solubles by ultra filtration;
treating the product, optionally in a jet cooker;
cooling; and
spray drying.
Further, a meat injection brine is disclosed, including as one of the ingredients the native protein material treated according to the indicated process. As an example, soy protein material is used. Also disclosed is a meat preparation injected with the soy protein material.
The invention further discloses meat analog products including, as one of the ingredients, the native protein material treated according to the indicated process. As an example, soy protein material is used.